Honeycomb catalytic assemblies and applications thereof

Abstract

In one aspect, catalytic assemblies are described herein. A catalytic assembly, in some embodiments, comprises a plurality of honeycomb catalyst segments bonded to one another by a bonding material, the honeycomb catalyst segments comprising an outer peripheral wall and a plurality of inner partition walls defining flow channels extending longitudinally through the catalyst segments, wherein the outer peripheral wall and inner partition walls have dispersed throughout a chemical composition comprising 50-99.9 weight percent an inorganic oxide composition and at least 0.1 weight percent a catalytically active metal functional group.

That which is claimed is: 
     
       1. A catalytic assembly comprising:
 a plurality of honeycomb catalyst segments bonded to one another by a ceramic cement, the honeycomb catalyst segments having a coefficient of thermal expansion (CTE) of 4×10 −6 /° C. to 8×10 −6 /° C. and comprising an outer peripheral wall and a plurality of inner partition walls defining flow channels extending longitudinally through the catalyst segments, wherein the outer peripheral wall and inner partition walls have dispersed throughout a chemical composition comprising 50-99.9 weight percent titania and at least 0.1 weight percent a catalytically active metal functional group; and 
 an outer coating surrounding axial dimensions of bonded honeycomb catalyst segments at the periphery of the catalytic assembly, wherein a peripheral honeycomb catalyst segment has a ratio of weight of the catalytic assembly to bonded area of the peripheral honeycomb catalyst segment of 0.02-0.25 Kg/cm 2 , the catalytic assembly operable to remain suspended for a time period of 60 seconds when raised by an apparatus coupled solely to the peripheral honeycomb catalyst segment, wherein the catalytic assembly is raised subsequent to thermal cycling 500 times from 150° C. to 500° C. to 150° C., the catalytic assembly heated to 500° C. by flowing a flue gas stream through the honeycomb catalyst segments of the assembly, the flue gas stream increasing in average temperature at a rate of 3.8-4.0° C./s and cooling the catalytic assembly to 150° C. at an average rate of 0.4-0.6° C./s. 
 
     
     
       2. The catalytic assembly of  claim 1 , wherein the honeycomb catalyst segments have a CTE of 5×10 −6 /° C. to 6×10 −6 /° C. 
     
     
       3. The catalytic assembly of  claim 1 , wherein the catalytically active metal functional group is operable for the selective catalytic reduction of nitrogen oxides. 
     
     
       4. The catalytic assembly of  claim 3 , wherein the catalytically active metal functional group comprises tungsten oxide, molybdenum oxide or vanadium pentoxide or mixtures thereof. 
     
     
       5. The catalytic assembly of  claim 1 , wherein the ratio of weight of the catalytic assembly to bonded area of the peripheral honeycomb catalyst segment is 0.03-0.08 Kg/cm 2 . 
     
     
       6. The catalytic assembly of  claim 1 , wherein a ratio of open frontal area of the catalytic assembly to open frontal area of a honeycomb catalyst segment of the assembly is at least 0.8. 
     
     
       7. The catalytic assembly of  claim 6 , wherein the ratio is at least 0.85. 
     
     
       8. The catalytic assembly of  claim 6 , wherein the ratio is at least 0.92. 
     
     
       9. The catalytic assembly of  claim 1 , wherein the ceramic cement comprises inorganic particles, inorganic oxide fiber and colloidal oxide. 
     
     
       10. The catalytic assembly of  claim 1  having a substantially circular cross-section of diameter at least 16 inches. 
     
     
       11. The catalytic assembly of  claim 10  having a diameter of at least 24 inches. 
     
     
       12. The catalytic assembly of  claim 1 , wherein the inner partition walls of at least one of the honeycomb catalyst segments have an average thickness less than or equal to 0.26 mm. 
     
     
       13. The catalytic assembly of  claim 1  having an open frontal area of at least about 0.65. 
     
     
       14. The catalytic assembly of  claim 1  having an open frontal area of at least about 0.73. 
     
     
       15. The catalytic assembly of  claim 1 , wherein the inner partition walls have an average thickness of less than or equal to 0.26 mm and the ratio of weight of the catalytic assembly to bonded area of the peripheral honeycomb catalyst segment is 0.03-0.08 Kg/cm 2 , the catalytic assembly having a substantially circular cross-section of diameter at least 18 inches and an open frontal area of at least 0.73, wherein a ratio of the open frontal area of the catalytic assembly to open frontal area of a honeycomb catalyst segment of the assembly is at least 0.85. 
     
     
       16. The catalytic assembly of  claim 15  having an isostatic strength of at least 5 Kg/cm 2 . 
     
     
       17. A catalytic assembly comprising:
 a plurality of honeycomb catalyst segments bonded to one another by a bonding material of a ceramic cement, the honeycomb catalyst segments comprising an outer peripheral wall and a plurality of inner partition walls defining flow channels extending longitudinally through the catalyst segments, wherein the outer peripheral wall and inner partition walls have dispersed throughout a chemical composition comprising 50-99.9 weight percent titania and at least 0.1 weight percent a catalytically active metal functional group, the inner partition walls having an average thickness less than or equal to 0.26 mm, wherein the catalytic assembly has a diameter of at least 16 inches, an isostatic strength of at least 5 Kg/cm 2  and a ratio of open frontal area of the assembly to open frontal area of a honeycomb catalyst segment of the assembly of at least 0.85. 
 
     
     
       18. The catalytic assembly of  claim 17 , wherein the inner partition walls have an average thickness of less than or equal to 0.22 mm. 
     
     
       19. The catalytic assembly of  claim 17 , wherein the catalytic assembly has a length of at least 150 mm.